Functions
FEM machines
Acoustics
FinEtoolsAcoustics.FEMMAcoustModule.acousticmass
— Methodacousticmass(self::FEMMAcoust, assembler::A, geom::NodalField, P::NodalField{T}) where {T<:Number, A<:AbstractSysmatAssembler}
Compute the acoustic mass matrix.
Arguments
self
= acoustics modelassembler
= matrix assemblergeom
= geometry fieldP
= acoustic (perturbation) pressure field
Return a matrix.
FinEtoolsAcoustics.FEMMAcoustModule.acousticstiffness
— Methodacousticstiffness(self::FEMMAcoust, assembler::A,
geom::NodalField,
Pddot::NodalField{T}) where {T<:Number,
A<:AbstractSysmatAssembler}
Compute the acoustic stiffness matrix.
Arguments
self
= acoustics modelassembler
= matrix assemblergeom
= geometry fieldPddot
= second order rate of the acoustic (perturbation) pressure field
FinEtoolsAcoustics.FEMMAcoustModule.nzebcloadsacousticmass
— Methodnzebcloadsacousticmass(self::FEMMAcoust, assembler::A,
geom::NodalField, P::NodalField{T}) where {T<:Number,
A<:AbstractSysvecAssembler}
Compute load vector for nonzero EBC for prescribed pressure.
Arguments
self
= acoustics modelassembler
= matrix assemblergeom
= geometry fieldP
= acoustic (perturbation) pressure field
FinEtoolsAcoustics.FEMMAcoustModule.nzebcloadsacousticstiffness
— Methodnzebcloadsacousticstiffness(self::FEMMAcoust, assembler::A,
geom::NodalField,
Pddot::NodalField{T}) where {T<:Number,
A<:AbstractSysvecAssembler}
Compute load vector for nonzero EBC for prescribed second-order pressure rate.
Arguments
self
= acoustics modelassembler
= matrix assemblergeom
= geometry fieldPddot
= second order rate of the acoustic (perturbation) pressure field
FinEtoolsAcoustics.FEMMAcoustSurfModule.acousticABC
— MethodacousticABC(self::FEMMAcoustSurf, assembler::A,
geom::NodalField,
Pdot::NodalField{T}) where {T<:Number, A<:AbstractSysmatAssembler}
Compute the acoustic ABC (Absorbing Boundary Condition) matrix.
Arguments
self
= acoustics modelassembler
= matrix assembler; must be able to assemble unsymmetric matrixgeom
= geometry fieldPdot
= rate of the acoustic (perturbation) pressure field
FinEtoolsAcoustics.FEMMAcoustSurfModule.acousticcouplingpanels
— Methodacousticcouplingpanels(self::FEMMAcoustSurf, geom::NodalField, u::NodalField{T}) where {T}
Compute the acoustic pressure-structure coupling matrix.
The acoustic pressure-nodal force matrix transforms the pressure distributed along the surface to forces acting on the nodes of the finite element model. Its transpose transforms displacements (or velocities, or accelerations) into the normal component of the displacement (or velocity, or acceleration) along the surface.
Arguments
geom
=geometry fieldu
= displacement field
n
= outer normal (pointing into the acoustic medium).- The pressures along the surface are assumed constant (uniform) along each finite element –- panel. The panel pressures are assumed to be given the same numbers as the serial numbers of the finite elements in the set.
FinEtoolsAcoustics.FEMMAcoustSurfModule.pressure2resultantforce
— Methodpressure2resultantforce(self::FEMMAcoustSurf, assembler::A,
geom::NodalField,
P::NodalField{T},
Force::Field) where {T<:Number, A<:AbstractSysmatAssembler}
Compute the rectangular coupling matrix that transcribes given pressure on the surface into the resultant force acting on the surface.
Arguments
self
= acoustics modelassembler
= matrix assembler; must be able to assemble unsymmetric matrixgeom
= geometry fieldP
= acoustic (perturbation) pressure fieldForce
= field for the force resultant
FinEtoolsAcoustics.FEMMAcoustSurfModule.pressure2resultanttorque
— Methodpressure2resultanttorque(self::FEMMAcoustSurf, assembler::A,
geom::NodalField,
P::NodalField{T},
Torque::GeneralField, CG::FFltVec) where {T<:Number, A<:AbstractSysmatAssembler}
Compute the rectangular coupling matrix that transcribes given pressure on the surface into the resultant torque acting on the surface with respect to the CG.
Arguments
self
= acoustics modelassembler
= matrix assembler; must be able to assemble unsymmetric matrixgeom
= geometry fieldP
= acoustic (perturbation) pressure fieldTorque
= field for the torque resultant
Algorithms
Acoustics
FinEtoolsAcoustics.AlgoAcoustModule.steadystate
— Methodsteadystate(modeldata::FDataDict)
Steady-state acoustics solver.
modeldata
= dictionary with string keys
"fens"
= finite element node set"regions"
= array of region dictionaries"essential_bcs"
= array of essential boundary condition dictionaries"ABCs"
= array of absorbing boundary condition dictionaries"flux_bcs"
= array of flux boundary condition dictionaries
For each region (connected piece of the domain made of a particular material), mandatory, the region dictionary contains items:
"femm"
= finite element mmodel machine (mandatory);
For essential boundary conditions (optional) each dictionary would hold
"pressure"
= fixed (prescribed) pressure (scalar), or a function with signature function T = f(x) If not given, zero pressure assumed."node_list"
= list of nodes on the boundary to which the condition applies (mandatory)
For absorbing boundary conditions (optional) each dictionary may hold
"femm"
= finite element mmodel machine (mandatory).
For flux boundary conditions (optional) each dictionary would hold
"femm"
= finite element mmodel machine (mandatory);"normal_flux"
= normal component of the flux through the boundary (scalar), which is the normal derivative of the pressure.
Output
modeldata
= the dictionary is augmented with
"geom"
= the nodal field that is the geometry"P"
= the nodal field that is the computed pressure (in the general a complex-number field)
Material models
Material models for acoustics
FinEtoolsAcoustics.MatAcoustFluidModule.bulkmodulus
— Methodbulkmodulus(self::MatAcoustFluid)
Return the bulk modulus.